House of Isildur
From Tolkien Gateway
The descendants of Isildur, elder son of Elendil. The House came close to destruction at the beginning of the Third Age, when Isildur and his three eldest sons were lost at the Disaster of the Gladden Fields. His youngest son Valandil was kept safe in Rivendell, however, and from him came the line of the Kings of Arnor that led over three thousand years to Aragorn II Elessar.